The excellent NeuroBollocks blog explains how transcranial direct current stimulation (TDCS) is an interesting idea: sending targeted, low-level electric currents through the brain with TDCS excites certain regions, which could have implications in treating depression and stroke victims. Plug in a patient for 20 minutes, and you could get the effects for up to days at a time. So foc.us is marketing $249 headsets ("Maximum 2 headsets per order.") that claim to "[e]xcite your prefrontal cortex," thus improving your gaming ability. To the company's credit, at least one study suggests hooking up a 9-volt to your skull could improve gaming ability, although that was all done in the lab, under professional supervision.